1. Field of the Invention
The present invention pertains to the field of radiation detectors which employ scintillating fibers. More particularly, the present invention pertains to the field of scintillating fiber radiation detectors which are used for homeland security.
2. Description of the Related Art
There is the possibility that radioactive materials, to be used in ‘Dirty Bombs’, can be sent to the U.S. from a foreign location. This can make them a threat to U.S. homeland security. Likely radio-nuclides for terrorist use include Cesium-137 and Cobalt-60 because of their (respective) penetrating radiation quantum energy (0.7 & 1.3 MeV gamma rays), long radiation half-life (30 & 5 years), and known technology for high activity radiation production (e.g., for medical use).
Shortcomings of current baggage, package, container, and portal radiation detection methods are i) the cost of detection equipment, ii) the cost of added personnel and training, iii) the detection delays for baggage, packages and passengers, iv) the possibility that detection can be cheated, and v) the possibility of travel delays or even travel cancellations due to false-positive radiation detection signals.
In addition, there is the possibility of catastrophic radiation exposure in the U.S. homeland, whether due to terrorism, war, nuclear accidents, or other man-made or natural causes. Such exposure may be latent or patent, and requires fast and accurate detection to provide security to those who might otherwise be affected.
The related art is shown in the following documents, each of which is incorporated by reference herein: Rad/Comm Systems Corp. web page describing the RC/3A Portable Radiation Detector (http://www.radcommsystems.com/hand.html); Amptek web pages describing the GAMMA-RAD and GAMMA-8000 portable scintillation probe (http://www.amptek.com/grad.html, http://www.amptek.com/gamma8k.html, and http://www.amptek.com/dpp.html); ComTec web pages describing a Low Power Scintillation Probe for (portable) MCA Systems (http://www.fastcomtec.com/fwww/datashee/det/naidet.pdf); web document from http://www.arcs.ac.at/G/volltext/ITRAP_Passed_Companies.pdf describing several radiation detecting systems; U.S. Pat. No. 5,780,856 to Oka et al. (Radiation Detector and Method of Detecting Radiation); U.S. Pat. No. 5,103,099 to Bourdinaud et al. (Device for Linear Detection of Radiation); U.S. Pat. No. 4,509,042 (Portal Radiation Monitor); Japanese Published Patent Application 9-243752 (Optical Fiber Type Large Area Radiation Monitor); Papers IAEA-CN-86/64 and IAEA-CN-86/63P from the 2001 International Conference on Measures to Prevent, Intercept and Respond to Illicit Uses of Nuclear Material and Radioactive Sources; 1993 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (vol. 1), pp. 606–608; Greelhood, Bruce, “An Overview of Non-Traditional Nuclear Threats”, PNNL-SA-36643; Proceedings of SPIE, v.3536, pp. 148–155; Seymour, Richard et al., “Flat-Panel, Scintillating-Fiber Detectors for Safeguards Applications”, submitted to INMM Annual Meeting, July 1998, Naples Fla.; Proceedings of SPIE, v.2551, pp. 108–117; Defense Horizons, Number 16, August 2002, pp. 1–12; NucSafe web pages describing scintillating glass fiber technology and sensors as well as PUMA panels and applications, including The Guardian™ Portable Radiation Search Tool; Saint-Gobain Scintillation Crystal Arrays and Assemblies brochure (05–02); TSWG web page describing NISUS; Bicron Scintillating Optical Fibers brochure (Saint-Gobain Crystals and Detectors); Radiation Oncology, Biology, Physics Volume 24, Supplement 1, 1992, page 288; and U.S. Nuclear Regulatory Commission Report NUREG/CR-5223, October 1988.
Allowed U.S. patent application Ser. No. 10/093,385 and corresponding U.S. Patent Application Publication 2003/0168602, both of which are invented by the instant inventor and incorporated by reference herein, reveal a “Scintillating Fiber Radiation Detector for Medical Therapy” that uses a 5 mm cross-section scintillating fiber and a photomultiplier tube attached to a rigid bed for detecting medical radiation.